Apr 6, 2015




Clinical Hub,Tools & Resources,UWHC Lab Test Directory,Histocompatibility

HLA Flow Crossmatch

HLA Flow Crossmatch (HCHLAFXM (if Pre-Tx), HCHLAFXB (if Post-Tx)) Histocompatibility Lab Test

Name: HLA Flow Crossmatch

Test Name: HLA Flow Crossmatch

Health Link Test Code: HCHLAFXM (if Pre-Tx), HCHLAFXB (if Post-Tx)

LIS Test Code: XMFLOWS (if Pre-Tx), XMFLOWB (if Post-Tx)

CPT Code(s): 86825x2

Test Component:

Includes flow cytometry crossmatch for T-cells (CD3+) and B-cells (CD19+) to test for HLA class 1 and 2 antibodies against a particular organ donor or potential donor.

Methodology: Flow Cytometry

Clinical Information:

Positive flow crossmatch may indicate increased risk of antibody mediated organ rejection.

Days Performed: Mon-Fri, 0800-1700.

In-Lab Turnaround Time: 2 - 5 days.

Stat In-Lab Turnaround Time: 4 hours.

Specimen: Blood

Collection Container: Red top

Also Acceptable: Red cap with yellow ring (SST)

Collection Volume: 4 mL

Pediatric Collection Volume: 1 mL

Stability Ambient:

8 days unseparated; 10 days serum separated

Stability Refridgerated:

8 days unseparated; 10 days serum separated

Stability Frozen:


Sample Analyzed: Serum

Testing Volume: 2 mL

Pediatric Testing Volume: 0.5 mL

Specimen Processing:

Note: above sample is for the recipient. Potential donor blood must also be collected and submitted, minimum of 9 mL of blood, collected in sodium heparin or ACD anticoagulant. Patient serum and donor cells may be available frozen in the UWHC HLA Laboratory- call for availability, and indicate if lab should use specimens from storage in the lab.

Specimen Transport:

Transport patient specimen at room temperature or refrigerated to UWHC Hospital Laboratory. Donor specimen must be collected, transported at room temperature, and received in the laboratory no later than noon on working days and within 2 days of collection.


The laboratory will produce a report of the determination of "positive", "negative", or "indeterminate", based on the change in fluorescent signal (delta MESF) compared to a median channel shift (MCS) from a negative control serum. A median channel MCS value will be reported, and may be useful for the clinician to assess the risk of transplant despite a result of "positive".


Results must be considered in conjunction with other laboratory testing (i.e., Luminex antibody testing) and clinical risk factors prior to transplant.


 T-cell (CD3) Result

 B-cell (CD19)  Result

 Clinical Interpretation



Negative: Compatible



Positive: Increased risk of rejection 


 Positive (strong)

Possible Class 2 antibody and/or weak Class 1 antibody



Non HLA-specific antibody or anti-Cw antibody(pattern has been

seen with weak Class 1 antibody)

 Positive (weak)

 Positive (weak)

Weak antibody, possible non-HLA antibody

Test Limitations:

Patients undergoing antibody modulation by means of IvIg therapy and having recent treatment by antibody-based immunosuppressant drugs (Rituximab, Thymoglobulin, Campath, etc) may present with a false positive flow cytometric crossmatch while lacking donor-specific HLA antibodies. Please alert the UWHC HLA Laboratory to anyrecent (within 2 months) immunosuppressive therapy.

Additional Information:

This test was developed and its performance characteristics determined by this laboratory.  It has not been cleared or approved by the US Food and Drug Administration. The FDA has determined that such clearance or approval is not necessary.  This test is used for clinical purposes.  It should not be regarded as investigational or for research. This laboratory is certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88) as qualified to perform high complexity clinical laboratory testing.